Office laminating machine



March 27, 1962 B. D. ElsNER ET AL OFFICE LAMINATING MACHINE 5Sheets-Sheet 1 Filed Aug. 28, 1958 [III-" l March 27, 1962 B. D. EISNERET AL OFFICE LAMINATING MACHINE 5 Sheets-Sheet 2 Filed Aug. 28, 1958 Z 5ENTORS James A. 51421 77777767" me qer zqgarman Jr! (MM 44%, 91%

fiiiorne s March 27, v1962 B. D. EISNER ET AL 3,027,

OFFICE LAMINATING MACHINE Filed Aug. 28, 1958 5 Sheets-Sheet 3 @4 2 vINVENTOR5 Z0?) 3 Ezs ner es 44.310 1 777 me r mgz/er Lzgyar man J'rgMarch 27, 1962 B. D. ElSNER ET AL OFFICE LAMINATING MACHINE 5Sheets-Sheet 4 Filed Aug. 28, 1958 INYENTORS gyrion D. 5157787 amesASwzm'mc-r mgz erLS arman My lii'orne s March 27, 1962 B. D. EISNER ETAL 3,027,285

OFFICE LAMINATING MACHINE Filed Aug. 28, 1958 5 Sheets-Sheet 5 U N m a gg BzzrZon gig}? 0 James A. wzmmer BY gI er Lbgyarman Jr:

4220 rngw United States Patent 9 3,027,285 OFFICE LAMINATING MACHINEBurton D. Eisner, Highland Park, James A. Swimmer,

Skokie, and Meyer L. Sugarman, Jr., Wilmette, 111., assignors toAmerican Photocopy Equipment Company, Evanston, 111., a corporation ofIllinois Filed Aug. 28, 1958, Ser. No. 757,779 16 Claims. (Cl. 156-4359)The present invention relates to. machines, for laminating documentsbetween sheets of transparent plastic.

It is an object of the invention to provide a laminating machine whichis particularly well-suited for oflice use and which is capable ofapplying an adherent-layer of plastic to both sides of a document orother sheet material to be protected. It is a related object to providea protective coating which is permanently bonded, which is impervious towater, ink and other liquids, whichis wear resistant, and which impartsa clear, bright, g-lossy appearance. In the latter connection, itis anobject to provide a macrine for protecting and beautifying descriptiveliterature, drawings, photographs and the like used for sales anddisplay purposes. It is also anobject to provide a machine which notonly preservesdocuments subjected to repeated handling, such asblueprints, price lists and the like, but also precludes the possibilityof tampering.

It is another object to provide a laminating machine which iscapable ofapplying uniform heat and pressure to the laminate for fusing of theadhesive thereon, and inwhich the same temperature and pressure isapplied over the entire width of the document insuring anoverall bond aswell as reliable sealing at the edges. It is a further object to providea laminating machine which comes up to operating temperature promptlyand maintains the proper temperature for all conditions of loading frommaximum load to the idle or stand-by condition.

It is a further object to provide a novel machine of the above typewhich is extremely rapid, producing a laminated document in a matter ofseconds, and which is capable of operating at a high speed on acontinuous feed' basis. In this connection, it is an object to provide amachine which accommodates large capacity rolls of plastic laminatingmaterial, requiring only infrequent replenishment and which turns outdocuments in the form of a continuous strip capable of being cut offindividually right in the machine if desired. The laminated documentsthus produced may vary in size from the maximum throat width of themachine to the size of file cards or even smaller.

In one of the aspects of the invention, it is an object toprovide amachine employing sheet material having a thermoplastic adhesive coatingwhich is fused 'at the region of contact with the document but which isprotected against premature fusion or sticking. It is a specific objectto provide a novel heated roller arrangement in which the temperature atthe surface is thermostatically maintained within desired limits butwhich cyclesat a rate which assures long contact life.

In another aspect of the invention, it is an object to provide alaminating machine having novel provision for controlling tension in theplastic material both before and after the laminating process. It isa.related and more general object, to provide a tension control meanswhich insures that the plasticmaterial is applied smooth- 1y, free ofany'bubbles, wrinklesor the like, and which insures: that the laminated.documents will lie flat, free of any tendency to curl in one directionor the other.

It is; another object of the invention to provide a machine which isconvenient to use, which has simple semi-automatic controls, and whichmay be used successfully by an unskilled operator without any specialtraining or experience. It is a correlative object to provide alaminating machine which, is light and portable and which maybe easilycarried from desk to desk enabling a single machine to accommodate anumber of users in the same oflice.

It is still another object of the invention to provide a machine whichhas a convenient and extensive feed table which may be swung fromworking position to an out of the way position for transport and.storage, protecting the mechanism against the entry of dust or foreignobjects. It is another object related to the foregoing to provide anovel housing in a machine of the above type which permits ready removalof the front plate or bezel for service and replenishment of the rollsof laminating material, :but in which all screws and fastening devicesare hidden from view and which has an attractive functional appearance.In this connection, it is an object to provide a laminating machinewhich'requires a minimum of servicing which consists of a. minimumnumber of parts, and which may be economically constructed andmaintained.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawings in which:

FIG. 1 is a perspective showing the external appearance of a machineconstructed in accordance with the present invention under operatingconditions.

FIG. 2 is an exploded view showing the removal of the front bezel in themachine of FIG. 1.

FIG. 3 is a right hand end view of the machine with portions of the endplate and end bell removed to show the details of the internalconstruction.

FIG. 3a is a detail showing the resilient mounting of the upper heatedroller.

FIG. 4 shows the heated rollers with the upper heated roller intransverse section taken along the line 4-4 in FIG. 3.

FIG. 4a shows the preferred distribution of the convolutions of thecoiled heating element.

FIG. 5 is a transverse sectional view of a supply roller inserted in theupper roller position.

FIG. 6 is a bottom view of the thermostat shown in FIG. 3.

FIG. 7 is a section of the supply roller mandrel taken along the line7-7 in FIG. 5.

FIG. 8 is a fragment showing the bezel retaining means taken along theline 8-8 in FIG. 3.

FIG. 9 is a schematic diagram of the electrical circuit.

FIG. 10 is a fragment showing the cutting means incorporated in the backof the housing.

FIG. 11 is a fragment illustrating the manner in which the end bells aresecured to the end plates. While the invention has been described hereinin terms of a preferred embodiment, it will be understood that we do notintend to limit ourselves to such embodiment bu intend to cover thevarious alternative and equivalen constructions which may be includedwithin the spirit and scope of the claims appended hereto.

Turning now to the drawings, and particularly to FIGS. 1-3 thereof, alaminating machine 20 is shown which is capable of receiving documentsfed in at the front and for discharging the laminated documents at therear,

with the documents being sandwiched'between two sheets of tightly bondedplastic film. The machine includes a frame having two end plates 21, 22which are laterally spaced from one another and which support thevarious rollers included within the machine. In the present embodiment,the endplates 21, 22 are of forwardly-facing L shape having ahorizontalportion 21a, 22a and a vertical portion 21b, 22b. Bridging the two endvplates is a front member 23, a top member 24-, and a back member 25(FIG. 3). For enclosing the end plates 21, 22 end bells 27, 28 areprovided which conform in profile to the end plates and which aresecuredto the latter. The means employed for fastening the variousmembers together will be described in detail at a later point.

It will be apparent that the structure as thus far described leaves openthe front of the machine except for that portion covered by the frontplate 23. Consequently, for enclosing the front of the machine and forsupporting and guiding documents into the'machine a bezel 3% is providedwhich is L shaped in cross section having a horizontal portion 31 and agenerally vertical portion 32 for mating with the horizontal andvertical portions respectively of the side plates 21, 22. In the presentinstance the bezel carries side flanges 33, 34 which are dimensioned totelescope snugly over the end bells 27, 28 when the bezel is assembledin operating position. The bezel is also provided with a lower flange 35or skirt and an upper flange 36 which extend over the edges of the frontand top members 23, 24 respectively to. produce a neat finishedappearance.

In accordance with one of the aspects of the invention,

the front surface 32 of the bezel is recessed as indicated at 3611, witha guiding wall 37 which tapers inwardly and downwardly. The horizontalportion 31 of the bezel is, moreover, extended inwardly to form a feedsurface or table 38, the junction of the members 37, 38 serving todefine an opening or slot 39 between them into which the documents arefed when the machine is in operation.

In accordance with another aspect of the invention, the bezel includes ahinged feed table or platen 40 which is pivoted along its rear edge at apivot 41 (FIG. 3) and which is swingable between a horizontal workingposition and an upraised storage or transport position. When the feedtable is in its horizontal position, it is supported by the horizontalportion 31 of the bezel and forms a smooth continuation of the feedsurface 38 so that documents may be smoothly guided from the forwardedge of the table 40 across the surface 38 and into the slot 39. Whenthe table 40 is swung upwardly the upper portion thereof nests in therecess 36a as shown by the dot-dash outline in FIG. 3, preventing entryofdirt or other foreign material into the document receiving slot 3?.

To facilitate guiding documents into the machine, a guide -42 isprovided at the left hand side of the table 40, such guide beingcontoured so that it registers with the sloping surface 37 when thetable is in its upwardlyswung, enclosing position.

For the purpose of applying heat and pressure during the process oflamination, a pair of vertically arranged heated rollers 51, 52 areprovided having a nip alined with the feed table 38, the ends of therollers being journalled in the respective side plates 21, 22. In orderto understand the mounting and construction of these rollers, the roller51, which is typical, is shown in transverse section in FIG. 4 to whichreference is made. it will be noted that the roller is of hollowconstruction comprising a metal cylinder having good thermal conductionproperties and end members or trunnions 53, 54 which are telescoped intothe ends of the cylinder. Preferably the end member 53, 54 are threadedinto the member 50 as shown to provide a unitary construction rigid inthe face of the applied pressures which may, nevertheless, bedisassembled.

For journalling the roller 51 in the side plates, ball bearings 55, 56are provided mounted in pivoted carriers 57, 58 to'permit bodilymovement of the roller. carrier 57 which is associated with the ballbearing is shown in detail in FIG. 3a. Here it will be noted that itincludes a stationary pivot 60 anchored in the side plate and an arm 61which is pulled downward by a coil spring 62 having an adjustable anchor63. An identical arrangement is provided at the other end of the roller51, and it will be understood that the springs are adjusted Here The

to provide equal biasing forces, causing the roller 51 to bear withequal pressure along its entire length. The mounting arrangement for theroller 52 differs from that of the roller 51 in that the roller 52 issupported by stationary carriers at each end. As shown in FIG. 3a theroller 52 is supported at its right hand end by a bearing carrier 65which is anchored to the adjacent end plate 22 by means of screws 66.

In accordance with the present invention a radiant heater is located atthe axis of each of the rollers 51, 52, the heater element including aradiation-transparent tube made of quartz or the like having containedtherein a longitudinally extending coil of resistance wire 73. Thequartz tube indicated at 70 is mounted in cup-shaped supports 71, 72which are preferably made of ceramic material with the joint beingsealed by suitable hightemperature cement. The coil of heating wire 73is axially arranged within the tube 70 and, in accordance with one ofthe more detailed aspects of the invention, the convolutions are moreclosely spaced at the ends of the heating element (FIG. 4a) to make upfor leakage of heat at the ends of the tube. The exact spacing betweenthe turns at each point along the element may be adjusted by one skilledin this art.

In order to provide electrical connection to the ends of the heatingelement, rod-like terminals anchored to the ends of the tube aretelescoped through the roller trunnions. Thus, at the left hand end ofroller 51, the heating element is connected to a terminal which isinsulated from the trunnion member 53 by a sleeve 81 of insulatingmaterial. Since the insulating sleeves provide thermal insulation aswell as electrical insulation, heat loss at the .ends of the element ismuch less than in conventional constructions. For the purpose of makingconnections to the outer end of terminal 80, a wiper 82 is providedmounted in a stationary support 83 formed of insulating material andsecured to the associated end plate. A similar construction is utilizedat the right hand end (FIG. 4), with a terminal 86 being brought outthrough an insulating sleeve 87 and contacting a wiper 88 which ismounted in an insulating supporting member 89. It will be apparent thatthis novel construction avoids the use of sliding contacts with theirattendant difiiculties and provide a reliable path for current flow intothe rotating cylinder. Moreover, the heating element including the tube70 with its attached terminals is readily replaceable simply by removingthe roller and unscrewing one of its ends.

It is found that the arrangement just described provides even, radiantheating of the inner wall of the roller 51 distinguished by quickresponse and therefore close following of the thermostatic controlswitch to be described. To facilitate heat absorption, the inner wallmay be colored black. The wire 73 of the heating element is preferablyformed of an alloy which is resistant to oxidation when operated atradiant temperatures. We prefer to use an aluminum iron alloy.Experience has indicated that it is not necessary to have a hermeticseal between the mounts 71, 72 and the quartz tube 70, the mounts beingpreferably formed of ceramic material which has a certain amount ofporosity. It would appear, however, that with the members 71, 72cemented in place, only a limited amount of oxygen is admitted to theinside of the tube thus limiting the rate at which oxidation can takeplace. It will be apparent that other well-known alloys may be used; forexample, alloys comprised of nickel, iron, chromium and generallyreferred to as Nichrome.

In carrying out the invention a resiliently mounted, stationarythermostat is provided having a sensitive element spection of FIG. 3. Itincludes bimetallic strip 101'which rides directly on the outer surfaceof the roller and includes a stationary contact arm 102 and a movablecontact arm 103. An adjustable stop 104- determines the normal positionof the fixed contact arm 102. At the tip of-the bimetallic element 101is a projecting pin 101a which engages the movable contact arm. 103.thereby opening and closing the contacts in accordance with theflexme ofthe bimetallic element 101.

In order to insure maintenance of physical contact between thebimetallic element and the roller, the. entire thermostat 100 is mountedat, the end of a light leaf spring 105 which is anchored with respectto, the end plates by a square rod 106. The spring 105 is preferablymuch lighter than the bimetallic strip. so thatthe latter may flex inresponse to temperature changes independently of the flow-up action ofthe spring. In short the bimetal constantly followsthe temperature ofthe movingroller. It will be apparent that where it is desired to changethe amount of forcewbetween the thermostat assembly and the roller 51,this may be accomplished simply by rotating the supporting bar 106through a small angle in one direction or the other. The construction ofthe thermostat 100a associated with the heated roller 52 need not, bedescribed in detail since it corresponds exactly to that previously setforth.

Thus, the temperatureof the heated rollers 51, 52 is subject toindependent automatic control, the upper thermostat preferably beingadjusted at the factory to a slightly lower control point than the lowerto compensate for the upwardly convected heat.

To produce a certain amount of anticipation and thereby minimize anytendency for the temperature to overshoot, particularly when the heatingelements are first turned on, the thermostat 100 is provided with anauxiliary heating element 110 of hairpin shape which is outwardly spacedfrom the periphery of the bimetal 101 (see FIGS. 3 and 6). Thisauxiliaryheater is arranged in series with the electrical contacts sothat when current is first applied (the contacts being initially closed)the bimetallic element receives a portion of its. heat from theauxiliary heater. Thus, the contacts tend tobe opened slightly inadvance of the controlpoint with little or no overshoot of thetemperature existing at the roller surface. In a practical case, theheating element may have a rating of 280 watts with a light runningcycle of 3 seconds on and 30 seconds oif and a load cycle of about 3seconds on and lseconds off. The relatively long of? portion of thecycle even under load is explained by the fact that the thermal capacityof the film and paper is low so that it takes very little heat to bringthe film and paper up to the operating temperature. It has been foundthat a temperature of230 F. may be maintained plus or minus about-. Thisis well within the limit temperatures of 210 F. to about 260 F. forpractical adhesives.

Having understood the construction of the heated rollers 51, 52 and themeans employed for heating such rollers, attention may next be given tothe supply roller-s which supply films of the transparent plasticlaminating material. An upper supply roller 121 serves to supply plasticfilm to the heated roller 51 while a lower supply roller 122 serves asthe source of film for the heated roller 52. The supply roller 121willbe taken as representative, corresponding numerals being applied tothe supply roller 122 with the addition of subscript a. The details ofconstruction will be apparent upon reference. to FIGS. 5 and 7, FIG. 5being a transverse fragmentary section with a roll of laminatingmaterial in place. Suchmaterial, indicated at 123, is wound about ahollow core 124 formed of cardboard or the like. For supporting the core124 in tight frictional engagement, a mandrel is. used having end pieces125, 126 and a resilient shell .127, all rotatably mounted on a shaft.130. As shown in FIG. 7., the resilient shell 127 has twosemi-cylindrical sections 128, 129 having sharp edges 13 1, 132, 133 and134 which 6 extend. radially outward. The. edges ,131---13:4v occupyonly the central portion of the mandrel and relief ispro- ;vided as at135, 136. so that all, of the sharp edges are individually sprung in.the outward direction. Thus, when for precise adjustment of the brakingforce.

a roll of laminating material. isforced onto the mandrel, the edges 131.134 are depressed inwardly as shown by the dot-dash outline in FIG- 7and tendfto bite. into the relatively softer cardboard. core. Eventhough the. force required to assemble. the roll in. place; may berelatively light, rotation between the roll and mandrel is effectivelyprevented.

In order to insure that the supply roll is seated in alined position, aroll stopv 140 in the form' of .an an.- nulardisk is securedto theendfmember by screws 141. And to insure that the mandrel itself isproperly located with respect to the frame of the machine, re-

taining washers .143, 144 are employed which may be of tion, theshaftis. locked against rotation and serves to support a. brake disk forapplication of predetermined drag upon the rotation. of the mandrel withprovision To. prevent rotation, the. shaft 130. is flatted as indicated,at

and the right hand end (FIGS. 3 and. 5.) is. received .the right handendof the shaft and whichpressesagainst .the plate 22. Keyed to the flatson the shaft 150, and

thus non-rotatable, is a brake disk which cooperates with a second brakedisk 156 of brake lining material screwed or otherwise secured tothe'end member 126 of the mandrel. Predetermined. braking force be-..tween the disks is obtained by a coil spring 158 which presses againstthe disk 155 and which is backed up by an adjustable thumb screw 159threaded on the shaft 130. It will be apparent that as the plastic filmis drawn from the supply roll relative rotation will take. place betweenthe two brake disks resulting in a drag which depends upon theadjustment of the screw 159. With the screw properly adjusted, the filmis tensioned and drawn perfectly straight over the guide bar, thus.avoiding any wrinkles, bubbles or the like in the final product. Theadjustment of the two supply rollers 121, 122 is preferably such as toproduce equal tension in the film being fed to the heated rollers,thereby to reduce any tendency toward curling of the laminate.

Forthe purpose of guiding the films from the. sup- .ply rolland forcausing the same to be trained or wrapped about the heated rollers overa predetermined arc, transverse polished guide bars rigidly secured tothe end plates are employed. Thus, referring to the upper supply roll,the film 161 therefrom passes about a guide bar which is so arrangedthat the film is. in contact with the heated roller 51 through an arc ofabout 80. Since the guide bar 160 contacts the back or nonadhesive sideof the film, there is no tendency for the film to stick to the bar eventhough the bar is located in a heated environment. Referring to thelower Supply roll 122, the film 162 therefrom is passed about a firsttransverse guide bar 163 and thence about a second guide bar 164. Whilethe guide bar 163 is in contact with the adhesive side of the film,nevertheless it will be noted that such bar is located at the. verybottom, i.e., the coolest part, of the housing and no. tendency' forsoftening or sticking of the adhesive is noted, even when the machine isoperated for long periods of time. Nor has any tendency been noted forthe accumulated heat to cause sticking of the film in either supplyroll. By way of insurance, a layer of insulation .sponse to the springpressure.

165 is used extending the width of the r311 121 between it and theheated rollers.

For the purpose of receiving and tensioning the larninate from theheated rollers 51, 52, and for discharg-.

ing it from the machine, vertically arranged pull rollers 171, 172 areprovided closely adjacent the heated rollers and having a nip alinedwith the nip of the heated rollers. The pull rollers are mounted onshafts 173, 174, and the driving means is so arranged that the surfacespeed of the pull rollers is slightly greater than the surface speed ofthe heated rollers 51, 52. The pull rollers are preferablymade of rubberor the like and are biased together by a leaf spring 175 at each end ofthe shaft 173, the frame end members being slotted to accommodatefloating movement of the shaft in re- For driving the rollers at properrelative speeds, a positive type belt drive is employed using a belt 180driven by a motor 179 suitably .secured to the frame plate 22. The belt180 is trained about a motor pulley 181, a heated roller drive pulley182 and a pull roller drive pulley 183, the diameters of the rollersbeing such that the overdrive of the pull rollers is in the order of onepercent. Slack 'in the belt 180 is taken up by an idler pulley 184. Forpositive driving of the upper heated roller 51 end gears are used,located at the opposite end of the machine from that visible in FIG. 3.Thus as shown in FIG. 4 the heated roller 52 is provided with an endgear 192 and the cooperating roller 51 is provided with an end gear 191,with such gears being in mesh with one another and having the same pitchdiameter as the diameter of the heated rollers. End gears are notprovided for the upper pull roller 171 since friction driving has beenfound to be adequate; however, end gears may be used if desired.

It is found that the .over driven pull rollers perform a number ofimportant functions. In the first place, since they are .alined with theheated rollers, they provide a straight pull upon the bonded laminateduring the critical cooling phase just after the laminate leaves thesurface of the heated rollers. This balances any residual strains in thelaminate so that the final product lies perfectly flat. It is also foundthat the pull rollers tendv to complete the laminating operation,ironing out any wrinkles or bubbles which may get by the heated rollers.This ironing effect may be due to the relative slippage which mustnecessarily take place because of the over-driving. In any event, thequality of the final product including freedom from bubbles andirregularities is believed to result from the combined action of the twosets of rollers, constructed and driven as described above.

As another feature of the present device, a serrated edge is providedimmediately adjacent to'the discharge side of the pull rollers 171, 172to facilitate the cutting off of individual laminated documents. In thepresent instance this edge occupies a recess 200 in the back of thecabinet, the recess being defined by bending the top member 24 inwardlyto form a forwardly inclined portion 24a and the back member 25forwardly to form a discharge shelf 2511 (FIG. 3). Between them, the twomembers 24a, 25a, define a discharge slot or outlet 201. Mounted alongthe lower edge of the portion 24a of the top member is a serrated blade205 which is held in place by struck out metal clips 206 (FIG. and byscrews 207. It is one of the features of the present construction thatthe lower edge of the member 24a carrying the blade is flared outwardlyso that the advancing edge of the laminate is sure to be guided throughthe discharge opening 201 and not hung up within the machine. In usingthe severing means described above, a document is fed into the receivingslot 39 at the front causing the laminate to be impaled on the serratededge of the blade and resulting in a clean tear across the a safely lowlevel.

It is one of the features of the device contributing to attractiveappearance that While the housing consists of a number of pieces, thefastening means for anchoring these pieces together is not readilyvisible. This is accomplished in part by providing inwardly turnedanchoring flanges on the front, top and back members 23, 24 and 25,indicated by the general numeral 210, and anchored by screws or the liketo the end members 21, 22 of the frame. In the case of the front panel23, the flanges thereon are pivoted along the lower edge as indicated at211 and a spring clip and detent 213, 21-4 is provided at the upper edgeof the panel to keep the same in place except when it is desired toreplenish the lower supply roll 122. For the purpose of enclosing theend plates and thereby hiding and protecting the mechanism securedthereto, the hollow end bells 27, 28 are'provided having threaded postsat spaced points engageable by screws passing through holes in the endplates. Thus referring to FIG. 11 which is typical, it will be notedthat the end bell 28 is provided with a post 220 which is threaded forreception of a fastening screw 220a extending through a hole in theadjacent end plate 22. The screws 220a are so positioned as to bereadily accessible when the bezel 30 and supply rolls 121, 122 areremoved. To insure that the bezel 30 remains in place,- while permittingready removal by a simple forward pull, guide rails 221, 222 are securedto the inside surfaces of the end plates 21, 22. The horizontal portionof the bezel 30 rests upon such guide rails and is retained in contacttherewith by spring clips, for example, as indicated at 224 in FIGS. 3and 8. The spring clips are suificiently strong so that the bezel cannotslip forwardly except with intentional effort.

Prior to mentioning certain advantageous features which are inherent inthe above construction, attention may be directed to the control circuitshown in FIG. 9. The circuit indicated generally at 230 has input lines231, 232 protected by, a fuse 233. In series with the line 231 is amaster switch 234 which supplies current to a bus 235. To indicate thatthe master switch 234 is closed, a pilot light 236 of the gaseousdischarge type is employed.

For supplying current to the motor 179, two switches, arranged inparallel, are used. The first is a switch 237 located right at the frontof the machine and the second is a foot switch 238 which is connectedinto the circuit by an appropriate line and connector.

In accordance with one of the aspects of the invention, means areprovided for disabling the motor circuit until the device comes up totemperature. This is accomplished by an auxiliary thermostat 239 of thenormally open type which is arranged within the machine in aheat-responsive position preferably in riding contact with one of theheated rollers, and adjusted to close once the desired thresholdtemperature is reached, remaining closed for all subsequent operation.In a practical construction the auxiliary thermostat may be mountedadjacent the control thermostat on the lower heated roller. To informthe operator when the machine is in readiness, a ready light 240 of thegaseous discharge type is employed bridging the motor and motor switchcircuit. Upon closure of the thermostat 239, the ready light 240 isenergized, informing the operator that the machine may be used. Uponclosure of either of the motor control switches 237, 238 the ready light240 remains lighted since the voltage drop through the motor is alwaysgreater than the striking point of the gaseous discharge lamp. Thethermostats 100, a continuously maintain the heated rollers 51, 52 atoperating; temperature as previously described, whenever the masterswitch 234 isclosed; It will be apparent to. one skilled in the artthatthe above described circuit positively insures that the machine willbe operated only when at operating temperature and consequently thereare no precautions to be-kept in mind on the part of the operator,enabling the machine to be operated successfully by inexperienced oflicepersonnel.

With regard to the choice oflaminating material, a polyester resin ispreferred since it-is distinguished by strength and long life. Suchmaterial may be coated with a suitable transparent adhesive, capableof'bonding to all types of paper within the temperature range set iiorthabove. Selection of an appropriate adhesive isa matter well'within theskill of the art.

As will be apparent to'one skilled inthe art one of the features of theabove-described construction is that the documents pass in'a straightlinefrom inlet to outlet, the feed table 38, 40 being located at thesame level as the junction between the heated rollers 51, 52. While themachine is compact, with thesupply rollers being located close to theheated rollers, premature fusion or sticking of the laminated materialis, nevertheless, avoided. Note that thelower supply rollerutilizes thespace under the feed table in the forward portion of the L, a locationwhichis inherently cool so that'there is no danger the adhesive willstick to the guide rod 163. Care need not be exercised in the insertionof documents since the surfaces 37', 38 form a funnel for guidance-ofthe document into the inlet opening or throat 39 where immediateengagement takes place with the advancing films. And, since both thefront bezel and back panel are recessed inwardly toward the rollers, thetotal traverse within the machine, i.e., from the inlet of the-heatedrollers to the outlet of the pull rollers is only a matter of a fewinches,

a distance which is a small fraction of the total thickness .of thehousing for minimizingwaste in the laminating of single documents.

Because of the simplicityand low costof the present machine, it may beused universally in business ofiices for the enhancement and protectionof documents and, where desired, for protectively laminating sheetmaterials other than paper.

While the invention has been described in accordance with a preferredembodiment'in which an adherent film is applied to both sides of asingle sheet, it will be apparcut that the invention is not limitedthereto but may be employed for covering only the face of a sheet. Thisis accomplished by feeding in two sheets back-to-back with subsequentseparation by trimming the edges. Consequently the term document as usedin the claims shall be understood to cover a single sheet'or two sheetsback-toback.

Finally, while the disclosed machine is primarily intended for applyingtransparent plastic films, it will be understood that it is applicable,in addition, to non-transparent, i.e., translucent, materials and tofilms made of material other than plastic.

What is claimed is:

1. In an oflice laminating machine, the combination of means providingan opening for receiving a document, a pair of heated rollers biasedtogether and arranged adjacent said opening means for driving. saidheated rollers, a pair of supply rolls each supplying a film oftransparent, laminating material having a thermoplastic sur-' 2. In anoffice laminating machine, thecombinationof means providing anopeningfor receiving a document, a pair of heated rollers biasedtogether and arranged adjacent said opening, means for driving saidheated rollers, a pair of supply rolls each supplying a film oftransparent adhesive coated laminating material to said heated rollersso that a document fed into said opening is bonded between two layers offilm by the action of heat and pressure, each of said heated rollersbeing of hollow construction having a radiant heating element located onits axis and having a, stationary thermostat riding on its surface andin intimate .heat trans.- fer relation therewith for controlling theenergization. of said element, and means. for lightly biasing thethermostats against said heated rollers.

3. In an office laminating machine, the combination of means providingan opening for receiving a document, a pair of heated rollers biasedtogether and arranged adjacent said opening, means for driving saidheated rollers, a pair of supply rolls each supplying a film oftransparent plastic laminating material to said heated rollers so that adocument fed into said receiving means is bonded between two layers offilm by the action of heat and pressure, at least one of said heatedrollers being of hollow construction having a radiant heating elementlocated on its axis and having a thermostat including a bimetallicelement riding on its surface for controlling the energization of theassociated heating element, said bimetallic thermostat having arelatively light mounting spring so that the. bimetallic element ismaintained in intimate contact with surface of said roller regardless ofthe condition of fiexure of such element.

4. In an oflice laminating machine, the combination of means'providingan opening for receiving a document, a pair of heated rollers biasedtogether and arranged adjacent said opening, means for driving saidheated rollers, a pair of supply rolls each supplying a film oftransparent plastic laminatingmaterial to said, heated rollers so that adocument. fed into said opening isbonded between two layers of film bythe action of heat and pressure, each of said heated rollers being ofhollow thin-walled construction having low heat capacity and having aradiant heating element located at its axis for direct radiation of theinside surface of the roller, said heating element comprising aradiation-transparent tube having a radiant resistor therein.

5. In an ofiice laminating machine, the combination of a frame providingan opening for receiving documents, a pair of heated rollers biasedtogether and arranged adjacentsaid opening, means on said frame fordriving said heated rollers, a pair of supply rolls each supplying afilm of transparent plastic laminating material to said heated rollersso that a document fed into said opening is sandwiched between twolayers of film and bonded together by the action of heat and pressure,each of said heated rollers comprising a hollow metal cylinder havinghollow trunnions at its ends and having a tubular heating elementlocated at its axis, said heating elements being formed of aradiation-transparent tube having a radiant coil longitudinally arrangedtherein and connected to terminal rods projecting from the ends of thetube, said terminal rods being telescoped into said hollow trunnions andinsulated therefrom, and wipers mounted on said frame for contacting theends of the terminal rods.

6. In an oflice laminating machine, the combination of a frame providingan opening for receiving documents, a pair of heated rollers biasedtogether and arranged adjacent said opening, means on said frame fordriving said heated rollers, a pair of supply rolls each supplying afilm of transparent plastic laminating material to said heated rollersso that a document fed into said opening is sandwiched between twolayers of film and bonded together by the action of heat and pressure,each of said heated rollers comprising a hollow metal cylinder of lowheat capacity having hollow trunnions at its ends and having a tubularheating element located at its axis, said heating elements being formedof a radiation-transparent tube having a radiant coil longitudinallyarranged therein and connected to terminal rods projecting from the endsof the tube, said terminal rods being telescoped into said hollowtrunnions and insulated therefrom, wipers mounted on said frame forcontacting the ends of the terminal rods and thermostats mounted on saidframe and riding on said heated rollers respectively for sensing thetemperature thereof and thereby controlling the energization of therespective heating elements.

7. In an office laminating machine, the combination comprising a frameincluding a pair of end plates laterally spaced from one another, a pairof heated rollers journalled in said end plates and biased toward oneanother, a pair of supply rolls journalled in said end plates forfeeding respective films of plastic between said heated rollers, a pairof pull rollers at the output of said heated rollers, means on at leastone of said end plates for driving said heated rollers and pull rollers,hollow end bells on said end plates respectively conforming in outlinethereto and covering said driving means, a front bezel shaped to overliethe front of the machines and having side flanges snugly telescoped oversaid end bells, said front bezel providing document receiving means inthe form of a slot immediately in front of said heated rollers for thefeeding of documents between said films of plastic material.

8. In an office laminating machine the combination comprising a frameincluding a pair of L-shaped end plates defining a forwardly facing stephaving ahorizontal portion and a vertical portion, a pair of heatedrollers journalled in said end plates and biased toward one another,said rollers being arranged one above the other and having a nipsubstantially alined with the horizontal portion of said step, an uppersupply roll journalled in said end plates at the upper portion of saidframe, a lower supply roll journalled in said end plates below thehorizontal portion of said step, means for guiding films of plasticlaminating material from said supply rolls about adjacent ones of saidheated rollers, a pair of pull rollers journalled in said end plates,said pull rollers being arranged one above the other immediately behindsaid heated rollers, and having a nip alined with the nip of the heatedrollers for defining a straight run of bonded laminate, means fordriving said heated rollers and, pull rollers, said supply rolls havingconstantly energized adjustable brakes respectively for applyingpredetermined and substantially equal tension to the films fedtherefrom.

9. In an ofiice laminating machine, the combination comprising a frameincluding a pair of end plates laterally spaced from one another with adocument-receiving slot extending between them, a pair of heated rollersjournalled in said end plates and biased toward one another, saidrollers being arranged one above the other and having a junctionsubstantially alined with said slot, an upper supply roll journalled insaid end plates'in the upper portion of said frame, a lower supply rolljournalled in said endplates in the lower portion of said frame,

smooth surfaced guide rods secured to said end plates for guidingrespective films of plastic laminating material from said supply rollsabout adjacent ones of said heated rollers, a pair of pull rollersjournalled in said end plates immediately behind said heated rollers andcentered with with respect to the latter, means for driving said heatedrollers and pull rollers, said supply rolls having brakes integraltherewith for constantly tensioning the film as it passes over saidguide rods.

g 10. In an office laminating machine a combination comprising a frameincluding a pair of L-shaped end plates defining a step having ahorizontal portion anda vertical portion, a pair of heated rollersjournalled in said end plates and biased toward one another, saidheatedrollers being arranged one above the other and having a junctionsubstantially coinciding with the horizontal. portion of said step,supply rolls associated with said heated rollers, means including filmguidesso that filmfrom said supply rolls is trained about said heatedrollers, means for driving said heated rollers, a front bezelmernherhaving a vertical portion and a horizontal portion for nesting in thestep formed in said end plates, the vertical portion of said bezelmember being rearwardly recessed and with the horizontal portion of saidbezel member being rearwardly extended to define a document receivingslot located immediately adjacent the input of said heated rollers, saidbezel member having an auxiliary pivoted feed table hinged along itsrear edge to said bezel and swingable between (a) a lowered position inwhich the feed table constitutes a forward extension of the .hori zontalportion of said bezel and (b) a vertical position in which saidauxiliary feed table encloses the front of said bezel.

11. In an office laminating machinea combination comprisinga frameincluding a pair of end plates laterally spaced from one another, a pairof heated rollers journaled in said end plates and biased toward oneanother, said heated rollers being arranged one above the other, supplyrolls associated with said heated rollers, means for drivingsaid heatedrollers, a front bezel member spanning said end plates, saidbezel-member having a face which is angled rearwardly and downwardly andwhich terminates in a document receiving slot located immediatelyadjacent the input of said heated rollers, and a pivoted feed tablehinged along its rear 'edge below said slot and swingable between alowered horizontal position for'feeding of documents into said slot anda vertical position which said feed table encloses the front of saidbezel including said slot. a

12. In an oflice laminating machine the combination com rising a frameincluding a pair of end plates laterally spaced from one another, a pairof heated rollers journalled in said end plates and arranged one abovethe other, means for supplying said heated rollers with films pftransparent laminating material, a pair of pull rollers journalled insaid end plates and arranged one above the other behind said heatedrollers, means for driving said rollers with the pull rollers beingdriven at a surface speed slightly higher than that of the heatedrollers so that a straightpull is applied to the laminate after thelaminate leaves the heated rollers for equalization of strains set up inthe laminate, a front bezel having a feed table, a rear panel having adischarge shelf, the feed table, the nips of the rollers and dischargeshelf all being in substantial alinement with one another so that adocument fed from said feed table proceeds in a straight line throughthe machine. I

. 13. In an office laminating machine thecombination comprising a frameincluding a pair of end plates laterally spaced from one another, a pairof heated rollers journalled in said end plates and arranged one abovethe p the nip between said heated rollers for receiving a document, arear panel having a discharge slot alined with the nip between said pullrollers for receiving the bonded laminate discharged from the latter,the front bezel being recessed convergently inward toward the feed slotand the back panel being recessed to provide a flare so that thereceiving and discharge slots are immediately adjacent said rollersthereby to provide a straight path of minimum length for said document.

14. In an office laminating machine the combination comprising a frameincluding a pair of end plates laterally spaced from one another, a pairof heated rollers journalled in said end plates and arranged one abovethe other, means for supplying said heated rollers with films oftransparent laminating material, a pair of pull rollers journalled insaid end plates and arranged one above the other behind said heatedrollers and centered with respect thereto, means for driving saidrollers, means hehind said pull rollers defining a discharge openingalined with the junction between said pull rollers for receiving thelaminate discharged from the latter, a cutting blade on one side of saidopening for severing the laminate upon applying relative movementbetween the laminate and the blade, said blade being mounted in angledposition to provide a tapered surface for guiding the leading edge ofthe severed laminate through said discharge opening.

15. In an office laminating machine the combination comprising anupstanding housing, the front wall of said housing providing a receivingslot for receiving documents to be laminated, a pair of heated rollerspositioned immediately behind said slot and vertically arranged todefine'a nip close to said slot and alined therewith, said heatedrollers being of hollow construction having radiant heating elementstherein as well as thermostatic means responsive to the roller surfacetemperature for controlling energization of the heating elements so thatthe temperature at the surface is maintained within close limits, supplyrolls arranged in said housing respectively above and below the heatedrollers, said supply rollers each having a strip of transparentadhesive-coated laminating material, means for guiding the strips oflaminating material from the supply rolls into arcuate contact with therespective heated rollers and into the nip thereof on opposite sides ofa document fed into said receiving slot, a pair of pull rollersvertically arranged closely adjacent said heated rollers, means forpositively rotating the heated rollers and pull rollers, the rear wallof said housing providing a discharge slot closely adjacent the pullrollers, means for establishing equal frictional drag upon the strips oflaminating material so that the strips are tensioned equally as they areheated in contact with the heated rollers and said pull rollers having anip which is symmetrically alined with the nip of said heated rollers toprovide a straight run of bonded laminate and having a surface speedwhich is just slightly greater than that of the heated rollers so thatthe tension is applied to the straight run of laminate as it cools andas it travels from the heated rollers to the pull rollers thereby toinsure equalization of strains set up in the laminating material forproduction of a flat bonded laminate.

16. In an ofiice laminating machine the combination comprising anupstanding housing having a Work table extending horizontally along thefront edge thereof, the front wall of said housing providing a receivingslot alined with the top of the Work table for receiving documents to belaminated, a pair of heated rollers positioned immediately behind saidslot and arranged one above the other to define a nip horizontallyalined therewith, said heated rollers being of hollow constructionhaving walls of low heat capacity and having heating elements there-inarranged to supply heat directly to the walls as Well as thermostaticmeans responsive to the roller surface temperature for controllingenergization of the heating elements so that the temperature ismaintained within close limits in spite of changes in loading, a firstsupply roll arranged above the heated rollers and a second supply rollarranged below the heated rollers and under said work table, said supplyrolls each having a strip of transparent adhesive-coated laminatingmaterial, means for guiding the strips of laminating material from thesupply rolls into arcuate contact with the respective heated rollers andinto the nip thereof on opposite sides of a document fed into saidreceiving slot, a pair of pull rollers vertically arranged adjacent saidheated rollers, means for positively rotating the heated rollers andpull rollers, the rear wall of said housing providing a discharge slot,means for establishing equal frictional drag upon the strips oflaminating material so that the strips are tensioned equally as they areheated in contact wtih the heated rollers, and said pull rollers havinga nip which is symmetrically alined with the nip of said heated rollersto provide a straight run of bonded laminate and having a surface speedwhich is just slightly greater than that of the heated rollers so thattension is applied to the straight run of laminate as it cools and as ittravels from the heated rollers to the pull rollers thereby to insureequalization of strains set up in the laminating material for productionof a flat bonded laminate, the pull rollers being arranged closelyadjacent the heated rollers and the front and rear walls of the housingbeing recessed inwardly so that the receiving and discharge slots formedtherein are closely spaced with respect to the rollers and so that thedocument travels a straight path of minimum length Within the machine.

References Cited in the file of this patent UNITED STATES PATENTS450,837 Kirby et al Apr. 21, 1891 1,514,288 Hynes Nov. 4, 1924 1,596,181Hills Aug. 17, 1926 1,955,508 Lofman Apr. 17, 1934 2,046,559 Javery eta1. July 7, 1936 2,171,259 Scott Aug. 219, 1939 2,425,686 Porter Aug.12, 1947 2,499,961 Lennox Mar. 7, 1950 2,621,423 Clark Dec. 16, 19522,680,468 Lewis June 8, 1954 2,750,310 Hodge Mar. 29, 1195 2,814,328less Nov. 26, 1957 2,822,030 Pokras Feb. 4, 1958 21,944,587 Newcomb July12, 1960 FOREIGN PATENTS 421,915 Great Britain Jan. 2, 1935 122,807Australia Nov, 14, 1946

6. IN AN OFFICE LAMINATING MACHINE, THE COMBINATION OF A FRAME PROVIDINGAN OPENING FOR RECEIVING DOCUMENTS, A PAIR OF HEATED ROLLERS BIASEDTOGETHER AND ARRANGED ADJACENT SAID OPENING, MEANS ON SAID FRAME FORDRIVING SAID HEATED ROLLERS, A PAIR OF SUPPLY ROLLS EACH SUPPLYING AFILM OF TRANSPARENT PLASTIC LAMINATING MATERIAL TO SAID HEATED ROLLERSSO THAT A DOCUMENT FED INTO SAID OPENING IS SANDWICHED BETWEEN TWOLAYERS OF FILM AND BONDED TOGETHER BY THE ACTION OF HEAT AND PRESSURE,EACH OF SAID HEATED ROLLERS COMPRISING A HOLLOW METAL CYLINDER OF LOWHEAT CAPACITY HAVING HOLLOW TRUNNIONS AT ITS ENDS AND HAVING A TUBULARHEATING ELEMENT LOCATED AT ITS AXIS, SAID HEATING ELEMENTS BEING FORMEDOF A RADIATION-TRANSPARENT TUBE HAVING A RADIANT COIL LONGITUDINALLYARRANGED THEREIN AND CONNECTED TO TERMINAL RODS PROJECTING FROM THE ENDSOF THE TUBE, SAID TERMINAL RODS BEING TELESCOPED INTO SAID HOLLOWTRUNNIONS AND INSULATED THEREFROM, WIPERS MOUNTED ON SAID FRAME FORCONTACTING THE ENDS OF THE TERMINAL RODS AND THERMOSTATS MOUNTED ON SAIDFRAME AND RIDING ON SAID HEATED ROLLERS RESPECTIVELY FOR SENSING THETEMPERATURE THEREOF AND THEREBY CONTROLLING THE ENERGIZATION OF THERESPECTIVE HEATING ELEMENTS.